Brain imaging in awake infants by near-infrared optical topography

Near-infrared spectroscopy for functional studies of brain activity in human infants: promise, prospects, and challenges

A recent workshop brought together a mix of researchers with expertise in optical physics, cerebral hemodynamics, cognitive neuroscience, and developmental psychology to review the potential utility of near-IR spectroscopy (NIRS) for studies of brain activity underlying cognitive processing in human infants. We summarize the key findings that emerged from this workshop and outline the pros and cons of NIRS for studying the brain correlates of perceptual, cognitive, and language development in human infants.

Fiber optic in vivo imaging in the mammalian nervous system

The compact size, mechanical flexibility, and growing functionality of optical fiber and fiber optic devices are enabling several new modalities for imaging the mammalian nervous system in vivo. Fluorescence microendoscopy is a minimally invasive fiber modality that provides cellular resolution in deep brain areas. Diffuse optical tomography is a non-invasive modality that uses assemblies of fiber optic emitters and detectors on the cranium for volumetric imaging of brain activation. Optical coherence tomography is a sensitive interferometric imaging technique that can be implemented in a variety of fiber based formats and that might allow intrinsic optical detection of brain activity at a high resolution. Miniaturized fiber optic microscopy permits cellular level imaging in the brains of behaving animals. Together, these modalities will enable new uses of imaging in the intact nervous system for both research and clinical applications.

The concept of 'developing the brain': a new natural science for learning and education

From the viewpoint of biology, learning and education can be defined as the processes of forming neuronal connections in response to external environmental stimuli, and of controlling or adding appropriate stimuli, respectively. Learning and education can thus be studied as a new field of natural sciences with the entire human life span as its subject, thus including various problems such as fetal environment, childcare, language acquisition, general/special education, and rehabilitation. Non-invasive imaging of higher-order brain functions in humans will clarify the brain's developmental processes, and will provide various evidence for learning sciences. This new approach is called 'developing the brain' or 'brain science and education'. The origin of the concept and its present state are described and its future prospects are briefly analyzed.

Absorber's Effect Projected Directly Above Improves Spatial Resolution in Near Infrared Backscattered Imaging

The spatial resolution of near infrared spectroscopic imaging in brain function mapping studies needs to be improved. Most near infrared spectroscopic imaging systems use optical fibers that are arranged like a lattice. The light source and the detector have one-on-one correspondence at intervals of about 3 cm. In this study, we apply several detectors against one source to improve spatial resolution. We assume that a local absorber within a strong scattering medium is a model for local cerebral activation. When we calculate absorbance, which is used to spectroscopically calculate hemoglobin concentration, the peak position shifts away from above the position where an absorber is located. As far as absorbance is calculated, we cannot obtain spatial information about the absorber even if many detectors are used against one source. When we calculate the difference between detected light intensities, however, we demonstrate that an absorber projected onto the measuring surface has an influence directly above it. We predict this property from a light diffusion equation and also prove it experimentally through measurements of a uniform resinous phantom with an absorber. This is one of the basic principles supporting the achievement of higher spatial resolutions with near infrared spectroscopic imaging.